The invention relates to the field of managed packet-oriented communications networks, and to be more precise it relates to obtaining passive measurements of end-to-end traffic parameters within such networks.
In the present context, the term “measurements” refers to measurements relating to network management and to measurements relating to service management, and in particular to quality of service (QoS) management.
Moreover, in the present context, the term “traffic” applies equally to flows of data packets and to data packets of a flow, and the expression “end-to-end traffic” means traffic passing right through a set of networks, a particular network or one or more domains or subdomains of a multidomain context network.
As the person skilled in the art is aware, the operators of managed networks frequently need to obtain values of traffic parameters or characteristics, such as jitter, packet loss rate, and transmission delay, and to do so with a certain amount of accuracy, in order to be able to monitor the operation of their networks. This enables them in particular to monitor the quality of service (QoS) guaranteed to their customers in service level agreements (SLA).
Traffic parameter values can be obtained actively or passively at certain network elements (equipments). The invention relates specifically to passive measurements on real traffic to be monitored.
These passive measurements determine the actual characteristics of real traffic and they require a large volume of data to be collected from the network peripheral equipments that constitute the ingress and egress points of the traffic (flows), followed by correlation of all the data collected.
In order to avoid overloading the network in terms of resources used by the quasipermanent increase in the volume of data that is collected, it has in particular been proposed to provide a branch connection to a traffic analysis unit for filtering and sampling the measurement data on each transmission link of each peripheral equipment, e.g. each router. This undoubtedly results in a significant reduction in the amount of measurement data sent to the network manager, but at the same time significantly reduces the accuracy of the measurements.
An object of the invention is to improve on this situation.